diff --git a/.github/workflows/ci_docker.yml b/.github/workflows/ci_docker.yml
index d97d613..fdd8fe7 100644
--- a/.github/workflows/ci_docker.yml
+++ b/.github/workflows/ci_docker.yml
@@ -22,6 +22,15 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v3
 
+      # avoid building if there are testing errors
+      - name: Run smoke test
+        run: |
+          sudo apt-get install -y libzbar0
+          python -m pip install --upgrade pip
+          pip install -r requirements-dev.txt
+          pip install .
+          pytest
+
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v2
 
diff --git a/src/extract_otp_secrets.py b/src/extract_otp_secrets.py
index b9f0818..ea0f331 100644
--- a/src/extract_otp_secrets.py
+++ b/src/extract_otp_secrets.py
@@ -92,10 +92,10 @@ Exception: {e}""")
     FONT_LINE_STYLE: Final[int] = cv2.LINE_AA
     RECT_THICKNESS: Final[int] = 5
     # PYTHON <= 3.7: must use () for assignments
-    START_POS_TEXT: Final[Tuple[Point]] = (5, 20)
-    NORMAL_COLOR: Final[Tuple[ColorBGR]] = (255, 0, 255)
-    SUCCESS_COLOR: Final[Tuple[ColorBGR]] = (0, 255, 0)
-    FAILURE_COLOR: Final[Tuple[ColorBGR]] = (0, 0, 255)
+    START_POS_TEXT: Final[Point] = (5, 20)
+    NORMAL_COLOR: Final[ColorBGR] = (255, 0, 255)
+    SUCCESS_COLOR: Final[ColorBGR] = (0, 255, 0)
+    FAILURE_COLOR: Final[ColorBGR] = (0, 0, 255)
     FONT_DY: Final[Tuple[int, int]] = (0, cv2.getTextSize("M", FONT, FONT_SCALE, FONT_THICKNESS)[0][1] + 5)
 
     qreader_available = True